Before 2005, wet-type water jet condensers commonly used in domestic sugar refineries are TDP-type water jet condensers. Since the Indian high-efficiency condenser was imported into China in 2005, sugar refineries in China followed to use such a condenser due to its obviously superior efficiency over that of a TDP-type water jet condenser. So far, most of sugar refineries from north to south in China are using this type of Indian high-efficiency condensers (including those imitated or improved by domestic factories). However, as having been used for nearly a decade, critical defects of this type of Indian high-efficiency condensers have been exposed gradually. For example, at the initial stage of grinding, most of these efficient condensers are high in vacuum degree, which can be within the range of 0.086 to 0.09 MPa, under the conditions of cold weather, low water temperature and stable quantity of steam treated. But when the production conditions change, for example, when the quantity of steam needing to be treated increases or sugar boiling time is shortened, or when a water feed temperature rises due to hot weather, the vacuum degree of a condenser will be seriously reduced to the range of 0.080 to 0.082 MPa, which does not meet the technological requirements of sugar boiling.